You are the camera, with only a "weapon" (or other held object) to represent the player moving through space. Optionally, an increasingly-damaged portrait of the character is featured in the UI.

There are no stairs or ramps. Every floor and ceiling in the game is at the same height. Every wall is a straight edge; instead of diagonal walls or curved hallways, there are only zig-zags.

Flat, 2D NPC's and items occupy a 3D space, and always face the camera (billboarding). Textures are pixelated and lack true dimension.

Door keys, health pickups, treasure, and ammo litter the ground, all awaiting collection by the player. There are only 4 weapons in the game!

Spamming the activate key on various walls sometimes reveals a hidden room with secret exits, items, or enemies.